Field of the Invention
The present invention relates to a method of manufacturing a pattern substrate and more particularly relates to, for example, a method of manufacturing a pattern substrate that is used to locate a component utilizing the surface tension of a liquid member.
Description of the Related Art
In recent years, researches on micro-mechanical systems called MEMS (Micro Electro Mechanical Systems) and micro-machines have been widely conducted In order to realize the micro-mechanical system formed with various components described above, it is necessary to provide an assembly system that can achieve mass production.
As a method of arranging a micro-component on a substrate, various types of researches on the autonomous locating of a micro-component are conducted. Specifically, researches utilizing a magnetic force and an electrostatic force, the surface tension of a molten solder, the surface tension of a liquid and the like are conducted.
However, with respect to the magnetic force, noise may be produced by a residual magnetic force. With respect to the electrostatic force, a component may be broken. Although advanced researches are conducted on the method utilizing the surface tension of a molten solder, and thus its practicality is high, a component vulnerable to heat cannot be used. In addition, a residual stress is disadvantageously produced by heat. On the other hand, in the method utilizing the surface tension of a liquid, there is no danger that the various components described above are damaged, and such a method is promising as the autonomous locating method (see, for example, Japanese Unexamined Patent Application No. 2005-317694 and Japanese Unexamined Patent Application No. 2011-227814).
In the autonomous locating method utilizing the surface tension of a liquid, in order to locate a micro-machine in a predetermined position on a substrate, it is necessary to perform lyophilic/liquid-repellent patterning on the surface of the substrate. Conventionally, as a method of performing the patterning described above, a method such as photolithography and etching is used. FIG. 11 shows a process chart of a conventional autonomous locating method utilizing the surface tension of a liquid.
A hydrophilic film 21 is first formed on a substrate B (FIG. 11A). Then, after a photoresist 22 is applied onto the hydrophilic film 21 (FIG. 11B), the substrate is set in an exposure device, and a mask pattern 23 is transferred. The exposed photoresist 22 is subjected to development processing (FIG. 11C), and the hydrophilic film 21 is etched according to the pattern of the photoresist 22 (FIG. 11D). Then, the photoresist 22 is separated, and thus on the substrate B, the hydrophilic film 21 where the pattern is formed is obtained (FIG. 11E). Then, in the same step as the pattern formation of the hydrophilic film 21, a liquid-repellent film 24 is formed on the substrate B (FIG. 11F).
When on the hydrophilic film 21 on the substrate 11 produced as described above, a liquid is applied, the liquid is spread but is prevented from being spread outside the liquid-repellent film 24, with the result that droplet 81 is formed (FIG. 11G). Then, when a component 9 is arranged so as to make contact with the droplet 81, the droplet 81 is spread even over the surface of the component 9 in contact with the droplet 81 (FIG. 11H), and thus the component 9 is autonomously located in a predetermined position by the surface tension of the droplet 81 (FIG. 11I).
As a method of adhering the located component 9 to the substrate B, there are various types of methods. The following three methods are typical adhering methods. In the first adhering method, as shown in FIG. 12, the hydrophilic film 21 of the substrate B is formed of SiO2, a SiO2 film 25 is formed on the surface of the component 9 in contact with the substrate B, water 82 to which an additive (such as hydrofluoric acid) for activating the SiO2 film 21, 25 is added is used as a droplet, the water 82 is evaporated and thus hydrophilic groups (OH groups) formed on the SiO2 film 21, 25 are coupled to each other. In the second adhering method, as shown in FIG. 13, water is used as the droplet 81, the water is evaporated and thereafter the periphery of the component 9 is fixed with an adhesive 26. In the third adhering method, as shown in FIG. 14, a droplet 83 containing an adhesive is used, the droplet 83 is dried and thus the substrate B and the component 9 are fixed.
Since in the method in which photolithography, etching and the like are used to perform patterning, it is necessary to use a mask or a plate, when the pattern is changed, time and money are disadvantageously needed. As a method of facilitating the change of the pattern, a method of controlling a liquid by arranging devices for generating electric and magnetic fields in a grid is proposed; however, disadvantageously, it is impossible to obtain only the accuracy of the locating lower than the size of the grid which can be produced, and as the region which can be controlled is made larger, the size of the device (circuit) is increased.